The present invention relates to a process for the preparation of choline oxidase by fermentation.
Heretofore, it has been known that choline oxidase is produced by a microorganism belonging to the genus Arthrobacter. Choline oxidase derived from the microorganism catalizes the conversion of choline chloride to betaine. By the conversion, hydrogen peroxide is also formed. A method for determination of choline by measuring the amount of hydrogen peroxide formed by the conversion has been proposed [Rinsho Byori (Clinical Pathology) 24, 461 (1976)].
It has now been found that a remarkable amount of choline oxidase is produced in the culture liquor and especially in the microbial cells, of a microorganism capable of producing choline oxidase and belonging to the genus Brevibacterium or Corynebacterium when cultured in a nutrient medium.
An investigation of the properties of the thus produced choline oxidase has led to the finding that betaine aldehyde is produced by oxidation of choline in the presence of choline oxidase and that betaine aldehyde is further converted to betaine by the action of the enzyme. Accordingly, choline oxidase obtained by the present process is useful for the quantitative determination of choline.